-Yes absolutely outside sunlight is the best and obvious choice if its warm enough where you live.
-The tube lights dont cost much to run. Spot/heat bulbs do, so use the lowest watt necessary to do the job. And instead of an overly hot bulb placed further away, use a lesser bulb closer - but guard against contact burns.
-Keep the chams in their own room, so that you can keep it warm in there and let the rest of your home be cooler in the winter at night (or if you live in a hot place, you can cool the cham room as needed and let it be warm for you if you can handle it.)
-If you cant house outside, Choose a room with a south facing window that opens (to let heat and fresh air in whenever practical).
-Choose a room next to your bathroom, so that you can re-direct shower humidty into the cham room with easy vent slits.
-Use a dripper for the primary water source along with a manual mister (the kind you pump by hand up to create pressure is very easy and not hard on your hands like a little spray bottle type - and creates more than enough mist for multiple chams).
-Raise your own feeders (reducing carbon footprint associated with shipping, and can reduce your waste if you feed off some of your vegetable scraps)
-When you first turn on the faucet to your bath or shower, collect the water in a bucket while you wait for it to warm up. Use that water for your chameleons instead of wasting it down the drain (assuming you have decent water - and best to leave it overnight for any chlorine to dissipate and allow water to reach room temp in the cham room).
-Install solar panels and/or a heat pump and/or a mini-wind turbine
